* {
    font-family: 宋体;
}

.head_title {
    font-size: 40px;
    color: rgb(0, 0, 0);
    font-family: 宋体;
    margin: 0 0;
}


.grade_selector {
    margin-top: 40px;
    text-align: center;
    display: block;
    width: 100%;
    height: 40px;
    padding: 0 10px;
    font-size: 16px;
    font-weight: bold;
    color: #333;
    border: 1px solid #ccc;
    border-radius: 5px;
    background-color: #f5f5f5;
}

.grade_selector option {
    color: #333;
    background-color: #fff;
}

.grade_selector:focus {
    outline: none;
    border-color: #66afe9;
    box-shadow: 0 0 8px 0 #66afe9;
}

/* .problem_list {
    list-style: none;
    padding: 0;
    margin: 0;
    border: none;
}

.problem_item {
    margin: 10px 0;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 5px;
    border: none;
}

.problem_number {
    font-size: 16px;
    font-weight: bold;
    margin-right: 10px;
    margin-top: 20px;
}

.problem_content {
    text-align: center;
    font-size: 26px;
    margin-bottom: 20px;
    margin-top: 20px;
    font-family: 宋体;
}

.answer_input {
    text-align: center;
    font-family: 宋体;
    padding: 5px;
    font-size: 22px;
    border-radius: 5px;
    border: 1px solid #ccc;
    width: 100%;
    box-sizing: border-box;
    margin: 20px 0;
}

.problem_divider {
    margin: 10px 0;
    border: 1px solid #ccc;
}

.result_right_text {
    font-weight: bold;
    color: #499fe4;
    font-family: 宋体;
    font-size: 18px;
}

.result_wrong_text {
    font-weight: bold;
    color: #ea2929;
    font-family: 宋体;
    font-size: 18px;
}
*/
.tips_text {
    margin: 10px 0px;
    font-family: 宋体;
    font-size: 18px;
    color: #000;
}

/*
.exam_result {
    position: fixed;
    font-size: 26px;
    color: rgb(0, 145, 255);
    top: 100px;
    right: 50px;
} */

.exam_list,
.content_table {
    box-shadow: -8px 12px 10px rgba(0, 0, 0, 0.23);
    background-color: #fff;
    margin: 20px 40px 80px 40px;
    padding: 10px 10px;
    font-family: 宋体;
    /* font-size: 24px; */
    border-radius: 6px;
}

.exam_list ul {
    list-style-type: none;
}

.exam_list ul li {
    margin-bottom: 0px;
    margin-right: 40px;
    display: flex;
    justify-content: space-between;
    border-bottom: solid 1px #77777749;
}

.exam_list ul li .title {
    font-weight: bold;
    font-size: 26px;
}

.exam_list ul li .description {
    font-weight: lighter;
    font-size: 20px;
}

.exam_list ul li button {
    margin: 5px 10px;
    border: none;
    color: #fff;
    border-radius: 6px;
    font-family: 宋体;
    font-size: 22px;
    width: 100px;
    height: 40px;
    float: right;
}

.exam_list ul li .useful:hover {
    background-color: rgb(18, 183, 245);
}

.exam_list ul li .useful {
    /* float: right; */
    background-color: rgb(63, 149, 234);
}

.exam_list ul li .useless {
    /* float: right; */
    background-color: rgba(0, 0, 0, 0.279);
}

.problem_list ul {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
}

.problem_item {
    margin: 30px 48px 0 25px;
    font-family: 宋体;
    padding: 10px 10px;
    width: 42%;
    border-radius: 5px;
    border: solid 2px #0000009b;
}

.center_text {
    text-align: center;
}

.right_item {
    border: solid 2px #02b6209b;
}

.wrong_item {

    border: solid 2px #ff01019b;
}

.problem_item input {
    width: 80%;
    height: 44px;
    padding: 5px;
    text-align: center;
    font-family: 宋体;
}

.problem_item .equation {
    font-size: 24px;
}

.problem_item p {
    word-wrap: break-word;
}

.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    /* 半透明的灰色背景 */
    z-index: 1;
    /* 设置遮罩层的层级 */
}

.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2;
    /* 设置内容区域的层级，确保其在遮罩层上方 */
}

.modal-content {
    /* 弹窗内容样式 */
    z-index: 3;
    max-height: 768px;
    overflow-y: scroll;
}

.modal-content::-webkit-scrollbar {
    width: 0;
    height: 0;
    color: transparent;
}

.statistics-container {
    margin: 20px 40px;
}

.stats {
    border: 1px solid #ccc;
    padding: 10px;
    margin-bottom: 10px;
    font-size: 24px;
}
